Tax Registration · United KingdomCompanies House created your company. HMRC still needs to hear from you.
We register UK businesses and their owners for Corporation Tax, Self Assessment, PAYE and the Construction Industry Scheme, so the right tax records exist before the first deadline arrives.
Business & Incorporation
At a glance
- Authorities
- HM Revenue & Customs (HMRC) · The Pensions Regulator (TPR)
- Forms & references
- SA1SA400SA401Starter checklist
- Registered with
- HMRC
- Corporation Tax
- Within 3 months of starting business activity
- Self Assessment
- By 5 October after the tax year you start
- PAYE
- Before the first payday, and no more than 2 months ahead
Overview
What it is, and why it matters.
Registering a company at Companies House, or starting to trade as a sole trader, does not register you for every tax. Each HMRC regime has its own registration, reference number and trigger point.
A limited company must add Corporation Tax within 3 months of starting business activity. Sole traders and partners register for Self Assessment by 5 October after the end of the tax year in which they start. An employer registers for PAYE before the first payday, even when the only person being paid is a director.
In construction, contractors paying subcontractors register for the Construction Industry Scheme (CIS) before the first payment. Subcontractors register so that deductions are made at 20% rather than 30%.
Who needs it
Who typically needs it.
- 01
Newly formed limited companies
Companies that have received their UTR and now need Corporation Tax set up with the right first accounting period.
- 02
New sole traders and partnerships
People starting self-employment, and partnerships that need their own UTR as well as one for each partner.
- 03
First-time employers
Businesses taking on staff, and directors about to pay themselves a salary through payroll.
- 04
Construction businesses
Contractors and subcontractors who need to be set up under CIS before payments start.
- 05
UK companies run from abroad
Companies whose directors live overseas and find HMRC’s online sign-up and posted activation codes awkward to deal with.
When you need it
The moments that usually trigger it.
- Your company has started trading, invoicing, buying stock or advertising.
- You’ve started working for yourself and haven’t registered for Self Assessment.
- You’re about to run payroll for the first time, even if it’s only a director’s salary.
- You’ve taken on your first subcontractor for construction work.
- You’ve formed a partnership, or a new partner has joined.
- HMRC has written to you about a UTR or a return you didn’t know you had to file.
Scope
Exactly what we handle.
Our engagement letter lists these specifically, so you know what is included before any work begins.
- 01
Adding Corporation Tax to the company’s HMRC account and recording the first accounting period correctly.
- 02
Registering sole traders and partners for Self Assessment, and partnerships for their own UTR.
- 03
Registering a PAYE scheme and obtaining the employer PAYE and Accounts Office references.
- 04
Registering contractors and subcontractors under CIS.
- 05
Setting up agent authorisation so we can deal with HMRC on your behalf.
- 06
Explaining your auto-enrolment duties to The Pensions Regulator when you take on staff.
- 07
Telling HMRC when a company is dormant or not yet trading, so it isn’t chased for returns.
- 08
Putting the first return and payment dates for each registration into one calendar.
The process
How it runs, step by step.
Timings depend on the authority and on how quickly documents come together. We tell you what’s typical for your case at the start.
Start with a conversationMap your registrations
We look at what you do, who you pay and when you started, and list which HMRC registrations apply and by when.
Gather references
We collect your company number, UTRs, National Insurance numbers and start dates, and set up our authorisation as your agent.
Register
We make each registration online in a sensible order: Corporation Tax first, PAYE before the first payday, then CIS if it applies.
Confirm and record
We check HMRC’s confirmation letters, record every reference number and set up your deadlines.
Hand over
You receive a summary of what is registered and what is due. If you use our filing or bookkeeping services, we carry on from there.
What we’ll need
The information to have ready.
A typical checklist. After the first conversation we send a version specific to your situation, so you don’t gather anything you don’t need.
Companies
- Company registration number and 10-digit company UTR
- Date the company started business activity
- The date the first accounts will be made up to
- Nature of the trade and registered office address
Individuals and partners
- Full name, date of birth and address
- National Insurance number, if you have one
- Date self-employment or the partnership started
- Any existing personal UTR
Payroll
- Date of the first payday and pay frequency
- Number of employees, and whether directors will be paid
- Workplace pension scheme details, if already chosen
Construction (CIS)
- Your CIS role: contractor, subcontractor or both
- Expected date of the first payment to or from a subcontractor
Please don’t email passports or bank statements. Once we’ve spoken, you’ll get access to a secure upload.
Common mistakes
Where this usually goes wrong.
The problems we are most often asked to fix, and what they tend to cost.
- Mistake 01
Waiting for trading to “really” start
Advertising, buying stock or hiring counts as starting business activity for Corporation Tax. Leaving registration beyond 3 months can bring a penalty.
- Mistake 02
Paying a director before PAYE exists
Salary paid before the scheme is set up has to be reported late, which can mean penalties and messy corrections to the director’s records.
- Mistake 03
Missing the 5 October deadline
Registering late for Self Assessment can bring a failure-to-notify penalty if tax is still unpaid after 31 January.
- Mistake 04
Mixing up UTRs
The company, each director and each partnership have separate UTRs. Using the wrong one misallocates payments and returns, which can take months to unpick.
- Mistake 05
Paying subcontractors without verifying them
Contractors must verify subcontractors with HMRC before paying them under CIS. Skipping it risks deducting at the wrong rate and owing the difference.
Worth knowing
The limits, stated upfront.
HMRC issues references and codes on its own timescales, often by post to your UK address.
Registering the PAYE scheme is separate from running payroll each month, which is a separate piece of work.
VAT registration is handled as its own service because it involves separate decisions about timing and schemes.
Where owners live outside the UK, their personal tax position in the UK and at home needs separate advice.
Questions
Tax Registration: frequently asked.
If yours isn’t here, ask us directly. We’ll answer in plain terms.
Ask a questionDoes Companies House register my company for Corporation Tax?
No. Companies House passes your details to HMRC, which posts a Corporation Tax UTR, but you still need to add Corporation Tax within 3 months of starting business activity.
What is a UTR, and how many will I have?
A Unique Taxpayer Reference is a 10-digit number HMRC uses for Self Assessment and Corporation Tax. A company has one, each person in Self Assessment has their own, and a partnership has a separate one.
Do I need PAYE if I’m the only director?
Usually, yes, if the company is going to pay you a salary. HMRC expects the scheme to be registered before the first payday, even when you are the only person on the payroll.
When do I need to register for Self Assessment?
By 5 October after the end of the tax year in which you started self-employment or first had income to report. If you started in the 2025–26 tax year, that deadline was 5 October 2026.
What if my company isn’t trading yet?
You can tell HMRC it is dormant, so it isn’t expected to file Company Tax Returns until it becomes active. It still files accounts and confirmation statements with Companies House.
Do I need to register for CIS?
If you are a contractor paying subcontractors for construction work, yes, before the first payment. Subcontractors can work without registering, but contractors then deduct 30% instead of 20%.
Related
Often needed alongside this.
The equivalent in our other countries
Speak with a consultant
Talk to us about tax Registration.
Pick the closest match and we’ll take it from there. You’ll get a written scope and fee before any work begins.
Or use our three-step guide, or email hello@fiscorra.com
